aboutsummaryrefslogtreecommitdiffstats
path: root/modules/util/io.go
blob: 69b1d63145a49a0bc5b07f5d0f9122f086049a68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package util

import (
	"errors"
	"io"
)

// ReadAtMost reads at most len(buf) bytes from r into buf.
// It returns the number of bytes copied. n is only less than len(buf) if r provides fewer bytes.
// If EOF occurs while reading, err will be nil.
func ReadAtMost(r io.Reader, buf []byte) (n int, err error) {
	n, err = io.ReadFull(r, buf)
	if err == io.EOF || err == io.ErrUnexpectedEOF {
		err = nil
	}
	return n, err
}

// ErrNotEmpty is an error reported when there is a non-empty reader
var ErrNotEmpty = errors.New("not-empty")

// IsEmptyReader reads a reader and ensures it is empty
func IsEmptyReader(r io.Reader) (err error) {
	var buf [1]byte

	for {
		n, err := r.Read(buf[:])
		if err != nil {
			if err == io.EOF {
				return nil
			}
			return err
		}
		if n > 0 {
			return ErrNotEmpty
		}
	}
}